Powder Coat Bullet Accuracy

by 10sandxs Sun Feb 28, 2016 12:50 pm

First topic message reminder :

As the accuracy of powder coated bullets has been the subject of discussion of late, Al and I did a methodical study to determine the effects of powder coating on bullet accuracy. To accomplish this, bullets were cast using a 5 cavity NOE mold # 453-200-SWC and a mixture of Wheel weight and linotype which when water dropped and aged gives a hardness of roughly 14 brinnell. Bullets from this mold and allow combination drop at 216 gr +/-.5 gr when I do my part well.

These bullets were weight sorted into groups of +/-0.3 gr and the heaviest group was used for testing. Of this group, half were lubed and sized with White Label Lube X-Lox2500+. The other half were coated with polyester powder coat (red) sourced form www.powederbythepound.com. Un-sized bullets were coated by the “Airsoft BB dry tumble” method and baked for 20 minutes at 420 degrees F. Thickness was determined to be between 1 and 3 thousandths by measuring coated and uncoated bullets prior to sizing. Once baked and cooled, these bullets were sized using the same sizing equipment (Star) that the previous bullets had been lubed and sized in.

These bullets were loaded using IMI Match brass which had been cleaned and prepared using normal loading methods. The load consisted of 4.5gr of Titegroup over a Federal Premium #150 Large Pistol Match primer seated to a depth of 1.230 +/-0.002 and crimped to 0.001 less than the body diameter with bullet seated.

This load was initially ransom rest tested from a base bolted to a concrete floor at an indoor range at 50 FEET. Three ten shot groups ranged from 0.431” to 0.615” for this load. The ransom rest on the indoor 50 YARD range consisted of the rest clamped to a 700 lb. (approximately) concrete and steel bench. The test protocol consisted of firing 5 ten shot groups of powder coated and traditionally lubed cast bullets. Previous 50 FOOT ransom rest testing indicated that within 1 or two “fouling” shots, the groups had stabilized and no significant effect was observed when switching between lubed and coated bullets (long line to short line simulation)

The test program was performed using two guns, a 45 I built on a Caspian frame and slide with a 5” Kart Exact Fit Barrel. This was the gun used for 50 FEET ransom rest testing. The second was a Rock River 6” gun that has shown excellent accuracy (>1.5”) in numerous previous ransom rest sessions. The second set of experiments with the Rock River was conducted for reasons discussed below. There was effectively no difference observed in the accuracy of these two guns.

Groups from the 50 YARD range were somewhat disappointing, ranging from a minimum of 2.065” to a maximum of 3.669”. Interestingly, these extremes were fired using the same gun/ammunition combination so user error or rest stability are possible factors. In many cases groups were reasonable with the exception of one or two flyers. To get a better understanding of the overall accuracy potential, group sizes are reported as both 10 shot and 9 shot groups.

Rock River powder – 2.466+/-0.072* and 2.153+/-0.235

Rock River lead – 2.825+/-0.578 and 2.356+/-0.522

Caspian powder – 2.589+/-0.672 and 2.008+/-0.426

Caspian lead – 3.088+/-0.289 and 2.231+/-0.422

* 4 groups, ran out of ammo.

In both guns for both 9 or 10 shot groups, power coating was MORE accurate in these tests by between .25 and .5” on average. Of course there appears to be some issues with either load development or ransom rest technique/anchorage which may not be allowing the guns/ammo combination to be performing to their highest level. I've also attached a graph of the average group sizes for all conditions for both 9 and 10 shot groups.

It should also be noted that while the average powder coat group size is better across the board then the lubed group size, the difference is still within the margin of error. I interpret this to mean that while power coat may (or may not) increase accuracy, it certainly doesn’t negatively affect accuracy.

Now with all that said, I’m open to questions, critiques, comments or suggestions for future experiments. Some things I’m planning, are to optimize load data for the range and bullet, chronograph testing to determine velocity and distribution.

by Magload Tue Jan 30, 2018 8:24 am

Thanks for this write up I have used both coatings for a couple of years till I started trying to shoot BE. I am looking forward to shooting coated bullets again after reading this. Don

by USSR Tue Jan 30, 2018 9:06 am

And here is the tried and true method:

No Shake, No Bake:
Cast your bullets using an alloy suitable for the intended pressure/velocity.
Run you bullets thru your Lubrisizer at +.001" - +.002" above slugged bore diameter.
Properly lubed and sized, leaves zero leading in your barrel.
Who the heck uses barrel popple holes or external compensators?
If you want 50 FPS more velocity, add a tenth or two more powder if determined to be safe.
When I shoot, I expect there to be some smoke.

Don

by 10sandxs Tue Jan 30, 2018 9:15 am

USSR wrote:And here is the tried and true method:

and this statement is the enemy of innovation...

by USSR Tue Jan 30, 2018 10:58 am

10sandxs wrote:
USSR wrote:And here is the tried and true method:

and this statement is the enemy of innovation...

Ah, but you have the solution to a problem that for the most part doesn't exist. Smile

Don

by 10sandxs Tue Jan 30, 2018 11:32 am

USSR wrote:
10sandxs wrote:
USSR wrote:And here is the tried and true method:

and this statement is the enemy of innovation...

Ah, but you have the solution to a problem that for the most part doesn't exist.

Don

It may not exist for you, but it does for others

by Chris Miceli Tue Jan 30, 2018 11:43 am

I think the accuracy came from the White Label Lube X. Smile

by Cheapshot Tue Jan 30, 2018 12:41 pm

igolfat8,
Great information, thank you very much. I will be trying out the proccesses this weekend.

David

by Slartybartfast Thu Feb 07, 2019 8:00 am

10sandxs wrote:
USSR wrote:And here is the tried and true method:

and this statement is the enemy of innovation...

While sometimes the reasoning of "we've always done it this way" is correct, other times certainly serves to fossilise the state of affairs and stifle change. Even change to something new but equal can be very beneficial because it maintains interest and brings in new competition.

And being limber and open to change helps fight external pressures. I raised an eyebrow at "when I shoot I expect a little smoke". Seems to me, smoke is lead and chemicals and particulates, costing money and time in health effects, range cleaning, filter and ventilation system requirements and maintenance.

by kidneyboy Thu Feb 07, 2019 8:34 am

10sandxs wrote:
USSR wrote:
10sandxs wrote:
USSR wrote:And here is the tried and true method:

and this statement is the enemy of innovation...

Ah, but you have the solution to a problem that for the most part doesn't exist.

Don
It may not exist for you, but it does for others

Yep, I do my best to not handle lead. Especially considering this is a hobby...

by lablover Fri Feb 08, 2019 7:23 pm

Anyone using bullets for coating without lube grooves? Wonder if a 200 gr swc with no lube grooves is any less accurate? No need for lube grooves when coating with Hi-Tek

by DA/SA Sat Feb 09, 2019 6:16 am

I haven't done any real testing, but after using then with and without lube grooves, (Acme and SNS Casting) I'm not so sure the no lube grooves don't shoot a bit better. It may have something to do with the difference balance of the projectile as it would be a bit heavier in the back.

I also usually shoot lead outdoors and coated indoors just out of courtesy to other shooters. I don't like to smoke up the indoor range if I can help it.

by S148 Sat Feb 09, 2019 9:18 am

lablover wrote:Anyone using bullets for coating without lube grooves? Wonder if a 200 gr swc with no lube grooves is any less accurate? No need for lube grooves when coating with Hi-Tek

https://www.ssusa.org/articles/2017/3/27/accuracy-of-lube-groove-vs-no-lube-groove-cast-bullets/

by Dr.Don Sat Feb 09, 2019 10:34 am

In 32acp I use two bullets from T&B: a 60gr swc conventionally lubed with groove, and a 64gr ungrooved but coated swc. My tests showed the coated ungrooved bullet to be slightly more accurate at 50 yds.

by Dr.Don Sat Feb 09, 2019 10:34 am

In 32acp I use two bullets from T&B: a 60gr swc conventionally lubed with groove, and a 64gr ungrooved but coated swc. My tests showed the coated ungrooved bullet to be slightly more accurate at 50 yds.

by Multiracer Sat Feb 09, 2019 11:35 am

Slartybartfast wrote:
10sandxs wrote:
USSR wrote:And here is the tried and true method:

and this statement is the enemy of innovation...

While sometimes the reasoning of "we've always done it this way" is correct, other times certainly serves to fossilise the state of affairs and stifle change. Even change to something new but equal can be very beneficial because it maintains interest and brings in new competition.

And being limber and open to change helps fight external pressures. I raised an eyebrow at "when I shoot I expect a little smoke". Seems to me, smoke is lead and chemicals and particulates, costing money and time in health effects, range cleaning, filter and ventilation system requirements and maintenance.

As a relative noob to this sport/hobby, I find plenty of resistance to many ideas to the point that it does not even turn into a conversation....weird !

by S148 Sat Feb 09, 2019 11:56 am

Dr.Don wrote:In 32acp I use two bullets from T&B: a 60gr swc conventionally lubed with groove, and a 64gr ungrooved but coated swc. My tests showed the coated ungrooved bullet to be slightly more accurate at 50 yds.

I just today ordered the 64 gr coated before I saw this!

What type of accuracy were you getting from those bullets? And could you share your load information? Thanks.

by lablover Sat Feb 09, 2019 12:53 pm

Yea, instead of getting into this coating game I think an order from bayou bullets is in order! I’m growing weary of this casting stuff....lol

by jglenn21 Sat Feb 09, 2019 2:56 pm

Multiracer, it's an old sport whose rules.have not changed much over the years so most things have been tried. New ideas or innovations seem to never be big changes.. the all time record score was shot many years ago with iron sights.

In many cases it's been there done that. Pistols have gotten better, red dots help, ammo is better yet it is still a struggle.to be very good. Thus the attraction to most of us.

by Dr.Don Sat Feb 09, 2019 4:44 pm

S148,

I was a beta tester of the 64gr bullet for Travis. I wrote a report of the results and posted it here:

https://www.bullseyeforum.net/t10849-32-acp-bullet-test-64gr-coated-swc?highlight=bullet+test

by S148 Sat Feb 09, 2019 7:11 pm

Don, thanks for the link. The information is very useful. I thought I'd try some in a 32 Long/H&R wheelgun just for fun, and wondered how they shot.

by Slartybartfast Sun Feb 10, 2019 10:54 am

jglenn21 wrote:Multiracer, it's an old sport whose rules.have not changed much over the years so most things have been tried. New ideas or innovations seem to never be big changes.. the all time record score was shot many years ago with iron sights.

Any grip over a 1911, any fully adjustable trigger, not being in contact with lead a lube. All great changes IMO.
But the discussion is often this is what works. Followed by see what's on the firing line. Followed by well try it then if you think you know so much.
Old sport is going to turn into dead sport if something doesn't change.

by jglenn21 Sun Feb 10, 2019 1:29 pm

"Old sport is going to turn into dead sport if something doesn't change."

I disagree but that is for another thread

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